Regulation of Intracellular pH in Plant Cells

Guern, J.; Felle, Hubert; Mathieu, Yves; Kurkdjian, Armen

doi:10.1016/s0074-7696(08)60693-2

Cited by 110 publications

(83 citation statements)

References 260 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been widely observed that H+ extrusion in aerobic plant cells is activated by agents that lower cytoplasmic pH, at least in part because the H+-ATPase exhibits a pH optimum lower than cytoplasmic pH (reviewed by Guern et al, 1991). Our results suggest that H+ extrusion by anoxic maize root tips also increases when cytoplasmic pH falls.…”

Section: Cytoplasmic P H During Anoxiasupporting

confidence: 50%

“…Vol. 11 1, 1996 ponent, not dominant, in a complex system regulating cytoplasmic pH (reviewed by Guern et al, 1991). Unfortunately, our understanding of the molecular bases for the other membrane transport systems and enzymes involved in H+ metabolism lags behind that for plasma membrane H+-ATPases.…”

Section: Contribution Of H + Lnflux and Extrusion To Cytoplasmic P Hmentioning

confidence: 99%

“…At present, we cannot distinguish between these alternatives. Determination of the molecular basis for H+ movement in living plant cells is hindered by a lack of specific inhibitors of H+-ATPases and other transport proteins (for review, see Serrano, 1990;Guern et al, 1991).…”

Section: Cytoplasmic P H During Anoxiamentioning

confidence: 99%

“…On the one hand, extrusion of HC by plant cells increases intracellular pH, if not muted by buffer or offset by compensating reactions. On the other hand, H+ extrusion by aerobic plant cells is activated by cytoplasmic acidosis (reviewed by Guern et al, 1991). Cytoplasmic pH falls after the onset of hypoxia and anoxia, so it is possible that rates of H+ extrusion may be more dependent on cytoplasmic pH than cytoplasmic pH is on Hf extrusion.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment

Xia

Roberts

1996

Plant Physiology

View full text Add to dashboard Cite

We tested the hypothesis that H+ extrusion contributes to cytoplasmic pH regulation and tolerance of anoxia in maize (Zea mays) root tips. We studied root tips of whole seedlings that were acclimated to a low-oxygen environment by pretreatment in 3% (v/v) O,. Acclimated root tips characteristically regolate cytoplasmic pH near neutrality and survive prolonged anoxia, whereas nonacclimated tips undergo severe cytoplasmic acidosis and die much more quickly. We show that the plasma membrane H+-AlPase can operate under anoxia and that net H+ extrusion increases when cytoplasmic pH falls. However, at an external pH near 6.0, H+ extrusion contributes little to cytoplasmic pH regulation. At more acidic external p H values, net H+ flux into root tips increases dramatically, leading to a decrease in cytoplasmic pH and reduced tolerante of anoxia. We present evidence that, under these conditions, H+ pumps are activated to partly offset acidosis due to H+ influx and, thereby, contribute to cytoplasmic pH regulation and tolerante of anoxia. l h e regulation of H+ extrusion under anoxia is discussed with respect to the acclimation response and mechanisms of intracellular p H regulation in aerobic plant cells.Root tips of whole maize (Zea mays) seedlings subjected to HPT with 3% (v/v) O, in N, survive longer under anoxia than NHPT tips (Saglio et al., 1988;Johnson et al., 1989). HPT root tips regulate cytoplasmic pH near neutrality for many hours, in contrast to NHPT root tips, which exhibit severe cytoplasmic acidosis early in anoxia (Xia and Roberts, 1994;Xia et al., 1995). Cytoplasmic acidosis can cause early death in hypoxic maize root tips (Roberts et al., 1984), and the extent of cytoplasmic acidosis in plants under low oxygen has been widely shown to correlate with their intolerance of this stress (reviewed by Kennedy et al., 1992 andRicard et al., 1994). It is therefore important to understand the factors and mechanisms contributing to intracellular pH regulation in plant cells under anoxia.One phenomenon that may be valuable in preventing cytoplasmic acidosis during anoxic stress is lactate efflux, which has been observed to be induced in maize roots during acclimation in 3% O, (Xia and Saglio, 1992;Xia and Roberts, 1994) and also in certain Limonium sp. (Rivoal and Hanson, 1993). Fermentation to cytoplasmic lactate leads to significant cytoplasmic acidosis (reviewed by Ricard et al., 1994). Therefore, it is possible that remova1 of cytoplasmic lactate by efflux might serve to limit acidosis. Such a pos- sibility depends in part on the fate of H+ generated during fermentation of Glc to lactate; H+ generation is stoichiometric with lactate at constant ATP (Hochachka and Mommsen, 1983). It is not currently known if HPT root tips excrete lactate anion or lactic acid or if cytoplasmic H+ produced during fermentation to lactate is pumped into the extracellular space or the vacuole.Saint-Ges et al. (1991) observed a correlation between cytoplasmic pH and ATP levels after the onset of anoxia in excised NHPT maize root tips....

show abstract

Section: Cytoplasmic P H During Anoxiasupporting

confidence: 50%

Section: Contribution Of H + Lnflux and Extrusion To Cytoplasmic P Hmentioning

confidence: 99%

Section: Cytoplasmic P H During Anoxiamentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment

Xia

Roberts

1996

Plant Physiology

View full text Add to dashboard Cite

show abstract

“…Loading cells with lipophilic weak acids is a convenient and efficient way of reducing intracellular pH (Guern et al, 1991). Tobacco cells were preincubated for 5 min with increasing concentrations of potassium propionate (pK 4.8) before being probed for their capability to accumulate [ 14 C]2,4-D (Fig.…”

Section: Influence Of ⌬Ph Changes On Membrane Auxin Transportmentioning

confidence: 99%

Short-Lived and Phosphorylated Proteins Contribute to Carrier-Mediated Efflux, but Not to Influx, of Auxin in Suspension-Cultured Tobacco Cells1

1998

Self Cite

View full text Add to dashboard Cite

Auxin is transported across the plasma membrane of plant cells by diffusion and by two carriers operating in opposite directions, the influx and efflux carriers. Both carriers most likely play an important role in controlling auxin concentration and distribution in plants but little is known regarding their regulation. We describe the influence of modifications of the transmembrane pH gradient and the effect of agents interfering with protein synthesis, protein traffic, and protein phosphorylation on the activity of the auxin carriers in suspension-cultured tobacco (Nicotiana tabacum L.) cells. Carrier-mediated influx and efflux were monitored independently by measuring the accumulation of [ 14 C]2,4-dichlorophenoxyacetic acid and [ 3 H]naphthylacetic acid, respectively. The activity of the influx carrier decreased on increasing external pH and on decreasing internal pH, whereas that of the efflux carrier was only impaired on internal acidification. The efflux carrier activity was inhibited by cycloheximide, brefeldin A, and the protein kinase inhibitors staurosporine and K252a, as shown by the increased capability of treated cells to accumulate [ 3 H]naphthylacetic acid. Kinetics and reversibility of the effect of brefeldin A were consistent with one or several components of the efflux system being turned over at the plasma membrane with a half-time of less than 10 min. Inhibition of efflux by protein kinase inhibitors suggested that protein phosphorylation was essential to sustain the activity of the efflux carrier. On the contrary, the pharmacological agents used in this study failed to inhibit [ 14 C]2,4-dichlorophenoxyacetic acid accumulation, suggesting that rapidly turnedover proteins or proteins activated by phosphorylation are not essential to carrier-mediated auxin influx. Our data support the idea that the efflux carrier in plants constitutes a complex system regulated at multiple levels, in marked contrast with the influx carrier. Physiological implications of the kinetic features of this regulation are discussed.

show abstract

Flow cytometric analysis of cytosolic pH of mesophyll cell protoplasts from the crabgrassDigitaria sanguinalis

et al. 1996

View full text Add to dashboard Cite

Phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) is a key enzyme of photosynthesis in C4 plants; it is specifically localized in the cytosol of mesophyll cells and is regulated by a phosphorylation/dephosphorylation process. The light‐dependent phosphorylation of PEPC is triggered by an increase in the cytosolic pH (pHc) of mesophyll cell protoplasts. An epifluorescence and confocal microscopy analysis showed that the specific pH probe 2′,7′‐bis‐(2‐carboxyethyl)‐5‐(and‐6) carboxyfluorescein, acetoxymethyl ester (BCECF‐AM), when used at low concentration, was essentially localized in the protoplast cytosol. By the nigericin null‐point method and flow cytometry, the pHc of freshly isolated protoplasts was estimated to be 6.4. To observe the full activity of PEPC kinase and maximal phosphorylation of PEPC in vivo, such protoplast suspensions must first be treated with a permeant weak base. The present report shows that 20 mM NH4Cl raised the final pHc to 7.4. This method can be useful for estimating rapid changes of pHc in plant cells. © 1996 Wiley‐Liss, Inc.

show abstract

Regulation of Intracellular pH in Plant Cells

Cited by 110 publications

References 260 publications

Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment

Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment

Short-Lived and Phosphorylated Proteins Contribute to Carrier-Mediated Efflux, but Not to Influx, of Auxin in Suspension-Cultured Tobacco Cells1

Flow cytometric analysis of cytosolic pH of mesophyll cell protoplasts from the crabgrassDigitaria sanguinalis

Contact Info

Product

Resources

About